Pass the Oracle Oracle PL 1z0-071 Questions and answers with CertsForce

D. True, after setting the DEPARTMENT_ID column to UNUSED, you can add a new column with the name DEPARTMENT_ID to the EMPLOYEES table. The UNUSED clause does not delete the column, it only marks it as no longer being used.E. True, once a column is marked as UNUSED, you cannot make updates to it. It becomes inaccessible for DML operations.

A, B, C, and F are not correct because: A. Once a column is set to UNUSED, it is not available for queries. B. The storage space is not immediately released after issuing a COMMIT; instead, the actual removal and space reclamation happen when you subsequently issue the DROP UNUSED COLUMNS operation. C. The DEPARTMENT_ID column is not set to null; instead, it's marked as UNUSED, which means it is no longer available for use. F. UNUSED columns are not placed into the recycle bin; they are just marked for deletion, and space can be reclaimed with the DROP UNUSED COLUMNS command.

References:

Oracle documentation on ALTER TABLE: Oracle Database SQL Language Reference

Understanding ALTER TABLE SET UNUSED: Oracle Database Administrator’s Guide

Both ROUND and TRUNC functions can be applied to numbers, and MOD is a function that returns the remainder of a division. The ROUND function rounds a number to a specified number of decimal places, which can be positive, zero, or negative. The TRUNC function truncates a number to a specified number of decimal places.

ROUND(MOD(25,3),-1) rounds the result of MOD(25,3), which is 1, to tens place, which results in 0. TRUNC(MOD(25,3),-1) truncates the result of MOD(25,3), which is 1, to tens place, which also results in 0.

Both are valid, but in this specific case, they give the same result because the remainder (1) when rounded or truncated to tens place (-1) will be 0.

B. True. CURRENT_TIMESTAMP returns the current date and time in the session time zone, which is determined by the SESSIONTIMEZONE setting.

E. True. CURRENT_TIMESTAMP returns a value of the data type TIMESTAMP WITH TIME ZONE.

A and D are incorrect because CURRENT_TIMESTAMP reflects the session time zone, not DBTIMEZONE. C is incorrect because CURRENT_DATE returns the current date with no time component, whereas CURRENT_TIMESTAMP includes both date and time. F is incorrect because SYSTIMESTAMP returns the current date and time from the system clock in the time zone of the database server, which can differ from the session's time zone affecting CURRENT_TIMESTAMP.

When creating an external table, which allows you to access data in a flat file as though it is a table inside the database, certain clauses are required:

A. the ACCESS PARAMETERS clause: This clause specifies the parameters required by the access driver to read the data files.

D. the LOCATION clause: This clause specifies the location of the data files that make up the external table.

References:

Oracle Database SQL Language Reference 12c, particularly the sections detailing the creation and management of external tables.

C. True. The error occurs because the alias "Department" used in the GROUP BY clause is enclosed in double quotes, which makes it case-sensitive. However, the column deptno is not originally created with double quotes in the table definition, so you cannot refer to it with a case-sensitive alias in the GROUP BY clause. Oracle interprets "Department" as a string literal, not a column alias, in the GROUP BY clause.

A is incorrect because you can use an alias in an ORDER BY clause. B is incorrect because an alias can contain space characters if it is quoted. D is incorrect because an alias does not always have to be specified in quotes, only when it includes special characters or spaces or if it is case-sensitive.

The correct statement to increase each employee's salary by the minimum salary for their department is:

D. This option correctly increases each employee's salary by the minimum salary in their department. The subquery calculates the minimum salary for the department of the current row being updated (e1) in the outer UPDATE statement. The subquery does not use GROUP BY since it returns a single value - the minimum salary for the matching department.

A, B, and C are incorrect. Specifically:

A uses a subquery with an aggregate function combined with GROUP BY, which is not needed and will result in an error.

B incorrectly references MIN(e1.salary) within the subquery, which is incorrect since e1 is the alias for the outer query's table and should not be used within the subquery.

C sets the salary to itself plus the minimum salary across all employees, not filtered by the department.

References:

Oracle Database SQL Language Reference, 12c Release 1 (12.1): "UPDATE"

A. The USER SYNONYMS view can provide information about private synonyms: This view contains information about private synonyms that have been created by the user. It lists all synonyms that are accessible to the user in their schema.

E. DICTIONARY is a view that contains the names of all the data dictionary views that the user can access: This view lists the names of all data dictionary views available to the user, providing a directory of useful database metadata.

Incorrect options:

B: The SYSTEM user does not own all base tables of the data dictionary; some are owned by SYS.

C: Not all users have access to dynamic performance views prefixed with V$; access is restricted based on privileges.

D: The USER_OBJECTS view lists all objects owned by the user, not just tables and views but also other types of schema objects like procedures and functions.

A: True. TRUNCATE is generally faster than DELETE for removing all rows from a table because TRUNCATE is a DDL (Data Definition Language) operation that minimally logs the action and does not generate rollback information. TRUNCATE drops and re-creates the table, which is much quicker than deleting rows one by one as DELETE does, especially for large tables. Also, TRUNCATE does not fire triggers.

References:

Oracle documentation specifies that TRUNCATE is faster because it doesn't generate redo logs for each row as DELETE would.

TRUNCATE cannot be rolled back once executed, since it is a DDL command and does not generate rollback information as DML commands do.

Synonyms in Oracle are aliases for database objects that can simplify SQL statements for database users.

A. The term "GLOBAL" is not used in the creation of synonyms in Oracle.

B. The statement without the keyword PUBLIC will create a private synonym that is only accessible to the user creating the synonym, not all users.

C. The correct syntax does not include PUBLIC as a prefix to the synonym name itself, making this option incorrect.

D. You cannot specify the SYS schema for creating synonyms, as it is reserved for system objects.

E. This is the correct syntax to create a public synonym, which makes the underlying object accessible to all users.

References:

Oracle Database SQL Language Reference, 12c Release 1 (12.1): "CREATE SYNONYM"

When writing SQL statements with multiple conditions in the WHERE clause, it's important to understand how logical operators like AND and OR work. These operators are used to filter records based on more than one condition:

The AND operator displays a record if all the conditions separated by AND are TRUE.

The OR operator displays a record if any of the conditions separated by OR is TRUE.

The precedence of these operators is also important: AND operations are always evaluated before OR operations unless parentheses are used to explicitly define the order of operations. Therefore, conditions enclosed in parentheses are evaluated first as per the standard SQL operator precedence.

Given this understanding, let's evaluate the options:

Option A uses parentheses to group the borrowed_date and transaction_type conditions together, ensuring these are evaluated first before the OR operator. This means the query will return records that meet both of these conditions or records with member_id 'A101' or 'A102', regardless of other conditions.

Option D does not use parentheses around the borrowed_date and transaction_type conditions but does use them to group the member_id conditions. Since the AND operator has higher precedence than the OR, this query will first evaluate the borrowed_date and transaction_type conditions, then evaluate the grouped member_id conditions. The outcome is records that have a borrowed_date of SYSDATE, a transaction_type of 'RM', and a member_id of either 'A101' or 'A102'.

The results of Options A and D are effectively the same, even though the use of parentheses is different. This is because in both cases, the evaluation of the borrowed_date and transaction_type conditions will be performed first due to their grouping by parentheses in Option A and the precedence of AND over OR in Option D. Therefore, they will both return all records where borrowed_date equals SYSDATE and transaction_type equals 'RM', plus any records where member_id is either 'A101' or 'A102'.

For further details on SQL operator precedence and logical operators, you can refer to Oracle Database SQL Language Reference 12c documentation, specifically the sections on conditional expressions.